Patent GB-359889-A (GB)
Title: Improvements in and relating to dyes and dyeing
IPC: C09B9/02
Filed: 1930-04-17
Abstract: Indanthrone derivatives; vat dyes, dyeing with; printing.-The tetrasulphuric esters of tetrahydrodianthraquinone-azine and its substitution products are converted into other sulphuric esters of reduced dianthraquinone-azines or -dihydroazines by treatment with oxidizing, reducing, or hydrolysing agents.  Moderate reduction converts them to the corresponding dihydroazines, which revert to the parent materials on exposure to air.  Further reduction leads successively to trisulphuric esters of tetrahydrodianthraquinone-dihydroazines, trisulphuric esters of anthrahydroquinone-anthranoldihydroazines, and disulphuric esters of dianthranol-dihydroazines.  The trisulphuric esters of the dihydroazines may be oxidized to the corresponding azines; on further oxidation, disulphuric esters of anthraquinone-anthrahydroquinone-azines are obtained.  The latter products may also be obtained by direct oxidation of the tetrasulphuric esters of tetrahydrodianthraquinone-azines or -dihydroazines.  On treating the tetrasulphuric esters of tetrahydrodianthraquinone-azines with acid hydrolysing agents, they are converted into the corresponding trisulphuric esters, while alkaline agents, such as strong caustic alkali, convert them into products which appear to be disulphuric esters of tetrahydrodianthraquinone azines substituted by hydroxy groups in the nucleus, the sulphuric ester groups being probably in different parts of the molecule.  These disulphuric esters, as well as the disulphuric esters of anthraquinone-anthrahydroquinone azines, differ from the known disulphuric esters derived from indanthrone in that they are developed to indanthrone dyes on the fibre by hydrolysis with dilute acid alone, without the addition of oxidizing agents.  In examples, (1) the tetrasulphuric ester of tetrahydro-dianthraquinoneazine (example 16 of Specification 334,902, [Class 2 (iii), Dyes &c.],) is reduced with zinc dust and caustic soda; the product appears to be an anthraquinone-anthranol-azine or dihydroazine trisulphuric ester, (2) the product of example (1) is oxidized with sodium hypochlorite, (3) cotton is dyed with the products of the preceding examples, the dyeings being converted to blue shades on treating with dilute hydrochloric acid, (4) the tetrasulphuric ester of tetrahydrodianthraquinone azine is reduced with caustic soda and hydrosulphite to the corresponding trisulphuric ester; the product, when dyed on cotton or wool, is developed to a blue shade with copper sulphate and hydrochloric acid, (5) the process of the preceding example is carried out with larger quantities of hydrosulphite to yield the trisulphuric ester of anthrahydroquinone-anthranol-azine or dihydroazine, (6) the same product is obtained by starting from the trisulphuric ester obtained in example 4, (7) the tetrasulphuric ester used in the preceding examples is hydrolysed to the corresponding trisulphuric ester by means of acetic acid, (8) the tetrasulphuric ester is treated with caustic soda solution; the product is dyed on cotton or wool and developed to a blue shade on immersion in dilute sulphuric acid, (9) the tetrasulphuric ester is treated with a weak hydrosulphite solution; the product (probably the tetrasulphuric ester of the dihydroazine) reverts to the parent material in contact with air, (10) the tetrasulphuric ester is oxidized with sodium carbonate and sodium hypochlorite to the disulphuric ester of anthraquinone-anthrahydroquinone azine, (11) the tetrasulphuric ester is reduced with zinc and acetic acid to the disulphuric ester of dianthranol-dihydroazine; the product is dyed on cotton and developed to a blue shade by treating with copper sulphate and hydrochloric acid, (12) the product of example (5) is dyed on cotton and oxidized on the fibre by means of caustic soda and hypochlorite; the brown shades obtained are converted to blue in a dilute sulphuric acid bath, (13) the tetrasulphuric ester of 3 : 31-dichlortetrahydrodianthraquinone-1 : 2.21 : 11-azine is partially hydrolysed to the corresponding trisulphuric ester by treating with acetic acid, (14) the product of example (13) is oxidized with potassium persulphate and caustic soda (or other alkaline oxidizing agents may be used) and the disulphuric ester of 3 : 31 - dichloranthraquinone - anthrahydroquinone - azine obtained is dyed on cotton and developed to a bright blue (3 : 31-dichlorindanthrone) in a dilute hydrochloric acid bath, (15) the trisulphuric ester of tetrahydrodianthraquinone-azine is oxidized by alkaline persulphate solution to the disulphuric ester of anthraquinone-anthrahydroquinone-azine, (16) the product of example (14) is pasted with glycerine and gum tragacanth, printed on cotton or wool, and developed in a dilute hydrochloric acid bath, and (17) the trisulphuric ester of tetrahydrodianthraquinone-azine is pasted with glycerine and gum tragacanth, printed on cotton or wool, and developed by copper sulphate and hydrochloric acid.  Specification 334,921, [Class 2 (iii), Dyes &c.], also is referred to.